From Roy Chapman Andrews' excellent book 'Across Mongolian Plains' published in 1921.

Photo by Tyler Quiring on Unsplash

Although the natives take such care for the repose of the spirit in after life, they have a strong distaste for the body from which the spirit has fled and they consider it a most undesirable thing to have about the house. The stigma is imposed even upon the dying. In Urga a family of Mongols had erected their yurt in the courtyard of one of our friends. During the summer the young wife became very ill, and when her husband was convinced that she was about to die he moved the poor creature bodily out of the yurt. She could die if she wished, but it must not be inside his house.

The corpse itself is considered unclean and the abode of evil spirits, and as such must be disposed of as quickly as possible. Sometimes the whole family will pack up their yurt and decamp at once, leaving the body where it lies. More usually the corpse is loaded upon a cart which is driven at high speed over a bit of rough ground. The body drops off at some time during the journey, but the driver does not dare look back until he is sure that the unwelcome burden is no longer with him; otherwise he might anger the spirit following the corpse and thereby cause himself and his family unending trouble.

Unlike the Chinese, who treat their dead with the greatest respect and go to enormous expense in the burial, every Mongol knows that his coffin will be the stomachs of dogs, wolves, or birds. Indeed, the Chinese name for the raven is the "Mongol's coffin."